The present invention relates generally to internal combustion engine but more particularly to an up-graded internal combustion engine have mechanical alteration to the connection of the piston and connecting rod to improve its performance.
Heretofore, conventional internal combustion engine, since its inception, and up to the present is built in a manner where the cylinder center axis always intersects the longitudinal axis of the crankshaft. Thus, when the reciprocating piston is on the dead center, the connecting rod lies vertically along the axis of the cylinder and the crankshaft. It was then realized that there is big power loss in the execution of the power stroke since the force in turning the crankshaft is gradually reduced up to the 90 degree turn of the crankshaft with respect to its vertical axis or the first quarter turn which is the most critical period of the power transmission. The force being transmitted by the connecting rod to the crankshaft is maximum when in the vertical position. Said force is reduced by the counter-force inherent to the crankshaft and further during the first quarter turn since the connecting rod creates a resultant force equal to the maximum force times cos .theta. which is lesser than the force being delivered when the connecting rod is in the vertical position (.theta. is the angle created by the connecting rod between the vertical axis of the cylinder and the center line of the connecting rod).
Since it is the desire to lessen the power loss of the aforementioned engine and to utilized as much power created by the combustion, some have moved the crankshaft sidewardly such that the vertical axis of the crankshaft and that of the cylinder lies in different planes and in order that the connecting rod would be substantially vertical in position as it approaches the 90 degree turn or the first quarter turn of the crankshaft. Such, however, is not possible without additional mechanical alteration as the connecting rod would be in contact with lower edge of the cylinder in the return stroke of the piston. An example of this alteration is by placing the piston wrist pin, where the connecting rod is attached, at lower portion of the piston. This alteration would free the connecting rod from the lower edge of the cylinder during the return stroke of the piston.
The initial findings of the engine appears satisfactory as the performance of the engine is improved by 20% more than the conventional. However, after a period of time, indication of unequal pressure being applied to the side wall of the cylinder is found as evidently shown by some scratches at the upper portion on one side of the cylinder and at the lower opposed side thereof. This defect is due to the positioning of the piston wrist pin at the lower portion of the piston. The push of the connecting rod to the piston wrist pin creates a sideward force that presses the lower portion of the piston to cylinder lower side wall resulting to the tilting of the piston. This construction therefore, applies imbalance pressure to the sidewall of cylinder that easily wears either the sidewall of the cylinder or the piston rings of the piston.